The invention relates to a spackling/repair product or powder that produces a color while containing water. After the product is applied and the product dries, the color changes from either red or blue to white.
Spackling compounds, joint compounds and patch repair products have been used for years to provide the desired smooth or textured coating over imperfections in building members such as wall board, plaster and other construction surfaces.
Typically. these compounds comprise a resinous binder, limestone, clay, lubricant, stabilizers and thickeners that are mixed with water to provide a paste like product. The paste like product is applied to the desired building member substrate with a trowel or other tool. The product hardens via drying so that the construction worker can then perform other desired operations over the thus hardened product such as sanding, taping, painting, etc.
So as to provide a clear indication to the construction worker that the surface is ready for performance of such additional operations, it is desirable that the spackle, joint compound or repair product contain a color indicator whereby color of the product changes after the applied product has dried.
While the provision of a color change indicator in such a product would superficially appear to be an easy task, the problem is made much more complex by the additional requirement that the product must be color stable during its anticipated inventory or shelf life. Accordingly, there is an even more specific need for a hardenable spackle/repair product that will change color upon drying while exhibiting enhanced color stability during long storage periods.
In accordance with the invention a ready to use product or powder is provided containing a color change agent that produces a color while containing water. After the product is applied, and the product dries, the color changes, preferably from either red or blue to white.
This product indicates when the applied product has dried. This allows for sanding, painting or re-application at the proper time for maximum performance. All the problems associated with post-application performance due to incomplete drying of the compound can be avoided.
Color change indicators that have been evaluated include phenolphthalein (red) and thymolphthalein (blue). These well-known indicators may change color after an alkaline mixture or solution containing same approaches neutrality. Also indicators can change color when water is lost. Water loss leads to the insolubility and precipitation of indicator solids which are colorless.
One specific formulation that has been tested is as follows:
The product is colored red to pink and turns white upon drying.
The pH of the above formula is preferably about 11-13 to promote enhanced stability of indicator color during the product application.
In general, the color change patch repair or joint or spackling compositions comprise surfactant, water retained agent, free-thaw agent, resin binder, pigment, filters, pH adjustment agent and the desired color change indicator. As used throughout these compositions are referred to generically as xe2x80x9cpatch repairxe2x80x9d compounds.
As to the surfactants that can be used, these can be chosen from a variety of commercially available compounds. These include the ethoxylated alkyl phenols, such as the Triton(copyright) products available from Union Carbide, the Tamol(copyright) products available from Rohm and Haas and the polyoxyalkylene glycol block polymers available for example from BASF.
The water retaining agent or thickener is preferably a cellulosic ether such as carboxymethylcellulose CMC, hydroxyethylmethylcellulose (HEC), hydroxypropylmethylcellulose, alkali swellable and/or associative thickeners, etc. All of these are commercially available. The preferred thickeners are available from Aqualon, Wilmington Del. with the CMC 7H and Natrosol products particularly preferred.
The freeze thaw agent is normally ethylene glycol, although glycols in general can be mentioned.
The resinous binder component can be chosen from the groups of (I) polyvinyl esters and polymers derived therefrom and/or (II) acrylic resin binders. Exemplary binders falling within the designation (I) include poly(vinyl acetate), poly(vinyl alcohol); polyvinyl (butyral); poly(vinyl chloride) etc.
Exemplary binders falling within the group (II) designation include acrylic polymers and copolymers. Usually, these contain copolymerized acrylic unsaturated monomers preferably copolymerized with other ethylenically unsaturated monomers. Acrylic unsaturated monomers include lower alkyl esters of acrylic or methacrylic acid having an alkyl ester portion containing between 1 to 12 carbon atoms as well as aromatic derivatives of acrylic and methacrylic acid. Useful acrylic monomers include, for example, acrylic and methacrylic acid, methyl acrylate and methacrylate, ethyl acrylate and methacrylate, butyl acrylate and methacrylate, propyl acrylate and methacrylate, 2-ethyl hexyl acrylate and methacrylate, cyclohexyl acrylate and methacrylate, decyl acrylate and methacrylate, isodecylacrylate and methacrylate, benzyl acrylate and methacrylate, and various reaction products such as butyl, phenyl, and cresyl glycidyl ethers reacted with acrylic and methacrylic acids, hydroxy alkyl acrylates and methacrylates such as hydroxyethyl and hydroxypropyl acrylates and methacrylates, as well as amino acrylates and methacrylates.
The acrylic monomers are preferably copolymerized with ethylenically unsaturated monomers other than acrylic monomers. Ethylenically unsaturated monomers other than said acrylic unsaturated monomers can include, for example, those monomeric materials exhibiting ethylenic double bond unsaturation such as polymerizable vinyl, allylic, fumaric, maleic, or like ethylenically unsaturated double bond functionality (carbon-to-carbon unsaturation) which can be copolymerized with the acrylic double bond unsaturation in said acrylic unsaturated monomers.
Ethylenically unsaturated monomers can include, for example, styrene alpha-methyl styrene and substituted alkyl styrenes, chlorostyrene, vinyl toluene, vinyl naphthalene, dibutyl maleate, butadiene, vinyl chloride, vinylidene chloride, acrylamide and acrylonitrile and similar ethylenically unsaturated monomers. The ethylenically unsaturated monomers can be copolymerized with said monomers containing acrylic unsaturation by free radical induced addition polymerization using peroxy or azo catalysts, common redox catalysts, ultraviolet radiation, or the like. The acrylic copolymer of this invention can be synthesized by adding a monomer mixture over a period of time to an aqueous polymerization medium in the presence of a free radical initiator or azo catalyst to produce an acrylic latex copolymer. Ordinarily about 1-2% peroxide initiators based on the monomer weight is used in the polymerization of monomers.
At present, and in order to impact enhanced color stability to the product, it is preferred to use a resin binder latex that has substantially no NH3 or ammonium salts contained in the latex. Most preferred is UCAR latex 412 which includes as the main polymeric component:
butyl acrylate(BA)/methyl methacrylate (MMA)/methacrylic acid (MA) polymer.
The BA repeat unit may be present in a molar amount of about 40-60% with the MMA present in an amount of about 40-60% and the MA present in an amount of about 0-5%. This particular latex comprises about 45 wt % polymer solids and water in an amount of about 53 wt %. In addition, it contains minor amounts of preservative, an anti-foam agent, anionic stabilizers and residues from free radical initiators. No ammonia or ammonium salts are used in the manufacture of this product. A nonylphenoxy poly(ethyleneoxyl)ethanol surfactant is reputedly present in this latex product in an amount of about 2 wt %.
Referring next to the pigments, these can be chosen from a variety of compounds including ground limestone, TiO2, satin white, etc.
Fillers such as fibers, glossy spheres, pearlites, vermiculites, talc, clays, etc., can also be added.
PH adjustment agents such as NaOH, KOH, K2CO3 and other bases can be used to regulate pH of the product to preferably, alkalinity.
Exemplary color change agents include phenolpthalein (reddish pink) (PTL) and thymolphthalein (blue) as set forth above. Additionally, ortho-cresolphthalein (red), ethyl bis(2,4-dinitrophenyl)acetate (blue-green), p-nitrophenol (yellow), m-nitrophenol (yellow), m-dinitrophenyl (yellow), 1,2,5-trinitrophenol (orange), and 2,4,6-trinitrophenol (orange) may be mentioned. These color indicators possess color when maintained at an alkaline pH then lose color upon drying of the product.
The compositions most preferred at this time (i.e., best mode) is as follows:
* -modified hydroxylethylcellulosexe2x80x94Aqualon Div. Hercules 
pH=11.8-12.8; density 14.8-15.00 lbs/gal; color=pink
In accordance with the invention, the artisan applies the repair composition to the requisite structural surface and, with the aid of a trowel or other tool, provides a smooth or textured surface. As applied, the product is in its colored (e.g. pink when PTL is used as the color indicator) state. Upon drying, the color changes to white thereby indicating to the artisan that additional treatments etc. may be performed on the thus treated surface.